The present invention relates to a safety wheel of a baby's wheeled chair for a baby to sit on and move around to learn to walk.
Referring to FIGS. 8 and 9, a conventional safety wheel of a baby's wheeled chair has a wheel part 6, a ball 4, and a confining block 7; the wheel part 6 has a recess 61; the confining block 7 is connected to the wheel part 6 with an arc trench 62 being formed between the block 7 and the wheel part 6. The ball 4 is confined in the arc trench 62; the arc trench 62 has an intermediate lower portion wider than the tell 4, and tapers towards two upper end portions, which are narrower than the ball 4.
In moving the baby's wheeled chair slowly, the ball 4 will roll in the lower portion of the arc trench 62, permitting the wheeled chair to continue moving.
When the baby's wheeled chair is moved very quickly, the ball 4 will move to, and engage, the upper portions of the arc trench 62 due to centrifugal force, stopping the wheeled chair from moving.
The ball 4 and the arc trench 62 can stop the wheeled chair when the chair moves too fast, and therefore protect the baby riding on the chair. However, it is found that the safety wheel has an disadvantage that the wheeled chair can't be stopped to protect the baby from hitting obstacles accidentally when it is moved backwards.